398 



Harris Ha'\W;horne Wilder 



small but conspicuous spine, of unknown value, is seen extending along 

 the middle line forwards from the prae-sphenoid. This furnishes origin 

 for the remaining muscles of the eyeball. 



Of the relations of the cranial nerves it may be said that the Optic 

 nerve was single and median, and entered the single eyeball in the middle ; 

 the Third arose as a pair in the normal way, but the two united after 



Fig. 22. Two views of the cranial floor of tbe monster shown in Fig. 21. 

 In (a) the bones are shown entire, except on the left side, where a portion of 

 the orbito-sphenoid has been removed; in (b) the entire orbito-sphenoid has 

 been taken away, thns rendering the optic and supra-orbital foramina con- 

 fluent. 



ns, nasal ; lac, lacrimal ; fr, frontal ; pa, parietal ; os, orbito-sphenoid ; as, ali- 

 sphenoid; bs. basi-sphenoid ; bo, basi-occipital ; ex. ex-occipital: .so. supra- 

 occipital ; pt, petrosal ; op, optic foramen ; sup, supra-orbital foramen : ro, 

 foramina rotundum et ovale, always confluent in the pig; mag, foramen 

 magnum. The Roman numerals designate the cranial nerves. 



passing through the superior orbital fissure into the orbit ; and that from 

 the Fourth nerve on the two lateral elements of each pair remained 

 distinct. It may be of some significance in this connection that the 

 anterior nasal nerves, previously noted, although they ramify a part 

 in which the reduction is marked and situated anterior to the compound 

 Second and Third nerves, yet remain distinct, as do the other parts of the 

 Fifth nerve, to which they belong. 



